Ferrous alloy



Patented Mar. 15, 1938 STATEfi No lilrawing- Application December 24,

Serial No. 181,601

i. Claim.

This invention relates to steel alloys especially adapted for use in lining cylinder sleeves for internal combustion engines and similar uses where it is necessary to have a material that is highly resistant to wear and corrosion, both at normal temperatures and at relatively high temperatures such as 800 F.

The term wear resisting" as applied to ferrous alloys may have different meanings. For instance, one piece of metal may work in contact with a piece of another metal and the one will show no wear and the other considerable wear. on the other hand, twopieces of different metals can work in contact under the'same conditions as in the first instance, and neither will show appreoiable wear, although the difierence in hardness between the metals may be as great in one instance as in the other. The tendency of a metal to pick up particles from another metal with which it is in working contact is aggravated as the temperature is increased. 4

Alloys which have good wear resistance at room temperature may wear rapidly when the operating temperature increases to the neighborhood of 800 F. The same is true as to corrosion resistance and an alloy which may exhibit satisfactory corrosion resistance at room temperature may corrode rapidly at a temperature in the neighborhood of 800 F.

and aircraft and the like, it has been necessary to produce an alloy which will have improved properties with respect to wear resistance and corrosion in that part of the cylinder which is subjected to the maximum heat. The wear re sistance, which is an object of this invention, is the ability of the alloy to resistpick-up" either under hot or cold conditions, and also show a minimum loss of size when subjected to the working contact of standard piston ring material. The products of combustion of an internal combustion motor are such that when deposited on the walls of a cylinder, which may be dry because of the heat conditions, may, when the motor is idle, have a corrosive eilect and it is, therefore, important that the cylinder liner of the motor shall be corrosion resistant. An alloy which will meet the requirements above stated In order to improve liners for the cylinders of internal combustion engines used in automobiles (CL "iii-125) and produce improved cylinder liners may he made up with a composition as iollows:

Per cent Carbon i.00to 3.00 5 Chromium .50 to 10.00 Nickel 3.00 to 161m Copper 3.00 to 0.50 Molybdenum .50 to e00 Silicon .50 to $.50 10 Boron .25 to 3.00 Manganese .25 to 0.00 Sulphur not over..., .5 Phosphorus not over-.. .5

Balance iron lit is important that the chromium and molyhdel5 num when taken together shall constitute not less than 4% of the alloy.

The advantages of an alloy made in accordance with this invention, as to wear resistance and corrosion are shown by the following results of comparative tests in whichthe materials tested were rotated against each other inside a furnace which was heated to a temperature of 800 F. and in an atmosphere of SO: gas. The results were as follows:

Lossin thodllil-m Corrosion 20 Material #1 .0005 Very slight ram-o- Run togcthe s n.

Piston ring iron .00075 Vgg slight corropiiigiim'fitaatiz: 13331? 332833:

In these tests material #1 was an alloy made in accordance with this invention in which the principal constituents, other than iron, were in the following proportions: 40

Per cent Car 2.73 Chr m 7.70 Nickel 13.90 Copper 5.88 Molybde m 2.02 Silicon 1.72 Bor 1.23

Material #2.is a known commercial alloy of recognized outstanding merit as an abrasion resistor of which the principal constituents, other than iron, are in the following proportions:

Per cent Carbon 2.32

Manganese .61 Silicon 1.66 Chromium 1.93

Molybdenum 3.20

The piston ring iron used in the above tests was a known commercial material that is extensively used in the manufacture of piston rings, the principal constituents of which, other than iron, are in the following proportions:

Per cent Total carbon 3.70

Silicon 2.70

Manganese .60 Phosphorus .55 Sulphur .05

point of steel to insure that the steel tube will still be strong enough to permit the spinning operation. While in the above method of lining a cylinder it is important that the lining alloy have a melting point not in excess of 2300 F.,

it is also possible to use the alloy in forming a lining by another method in which the melting point of the alloy is not so'vital. In this latter method the molten alloy is poured into a spinning cylinder which is practically at room temperature, and in this case the lining material does not adhere to the cylinder, whereas in the first method the lining material is bonded to the cylinder.

An alloy made in accordance with the above formula bears a resemblance to the alloy known as Ni-Resist, in that the nickel and copper proportions are substantially the same in both 9.1- loys. However, NiResist is an austenetic cast iron, whereas my improved alloy is not an austenetic cast iron. There is also a difference between the two alloys in that the coefficient of expansion of NiResist is definitely greater than that of my improved alloy.

. Having thus described my invention, I claim:

An alloy steel consisting of 8 to 16% of nickel, 3 to 6.5% copper, 0.5 to 10% chromium, 0.5 to

' 4% molybdenum, the chromium and molybdenum together being not. less than 4%, 0.25 to 2% manganese, 0.25 to 3% boron, 1 to 3% carbon, sulphur not over 0.5%, phosphorus not over 0.5%, silicon 0.5 to 2.5%, and the balance iron.

GEORGE CHARLTON. 

